1. Field of the Invention
The present invention relates to devices, methods, and programs for estimating the status of an ultraviolet curable resin.
2. Description of the Related Art
Ultraviolet curable resin has been used as adhesive in assembling optical devices and electronic devices. Because it is difficult to measure the cure degree of ultraviolet curable resin by visual inspection, measurement is normally done by destructive inspection. In cases where an ultraviolet curable resin is used in a factory line, the cure degree is indirectly managed by managing the luminance of curing ultraviolet radiation and time of irradiation and by conducting a destructive test on a sample by sampling inspection.
Recently, a nondestructive inspection method is known whereby the status, i.e., the cure degree, of an ultraviolet curable resin is estimated based on time-dependent change in the intensity of fluorescence produced when the ultraviolet curable resin is irradiated by ultraviolet radiation (see, for example, patent document No. 1).    [patent document No. 1] JP 2007-248244
However, the intensity of fluorescence from some ultraviolet curable resins changes with an elapse of time after curing. Therefore, the method disclosed in patent document No. 1 may only be capable of accurately estimating the status of an ultraviolet curable resin immediately after the resin is irradiated by ultraviolet radiation.
Further, since the fluorescence intensity varies depending on the amount of coating made of ultraviolet curable resin, the method disclosed in patent document No. 1 may not be able to estimate the status of the ultraviolet resin with high precision.